external pump for long distance (head)?

i'm going to be installation the genesis reef systems auto water change, auto top off, and replenish modules soon, and i need to run a couple pumps from my basement, to my attic where the metering reservoirs will be. it is about 8 feet up, 15 feet across, then 12 feet up, a total of about 35 feet of head pressure.

do any of you folks have experience with an external pump that is reliable for this type of application. one will be in my fresh RO/DI water 32g container and the other in my prepared salt water 32g container that i will prepare with bulkheads for installation.

i only need the pumps to produce 100gph by the time they reach the attic but i find that a lot of the pumps i'm looking at have "quit head heights" but then a foot before that it is pumping 1600gph which i don't understand. how can a foot of more head height create so much backpressure that you can go from 1600gph to 0?

also, would it be possible to increased the potential head of the pump by reducing the output from say 1.5" to 3/4" like a velocity stack design?

thanks for any help you can provide!

You are really only pumping up 20ft. Since 12 of it is horizontal, it doesn't add that much to head pressure.

Reducing the diameter, you actually increase the back pressure.

both Iwaki and blue line make nice reliable pumps the biggest problem I see is the head height and only needing such a small flow it will need to be dialed down some I think... Here is a link to them at 21 foot head height you are looking at 700 to 800 gph, of course you will have some loss of flow so you will have to play with the pump some to get it dialed in..
External Aquarium Water Pumps, Fish Tank Inline Water Pump - AquaCave.com

thank you both very much. i'll likely just pick up an iwaki i guess. noise really isn't a problem as it will be in the basement away from common areas, so that's good. thank you for the information and helpful notes.

additionally, if anyone has specific experience pumping that distance with a specific pump, please reply. thanks!

The Blue Line / Iwaki / Pan World pumps are pretty quiet. Once i figure out how to properly reduce the vibration on the floor of my stand you wont even be able to hear mine